Beautiful jacket! I love the lapel roll.
If you are not sure about the cross zip, then probably a cross button would look the same but tamer and perhaps a bit more formal, can button only one button doesnt have to start from the bottom like a zipper
In reality you probably only see 1 one or 2 buttons, the rest just button holes... ok you might see a bit more buttons if worn unbuttoned ... but when I wear jacket with buttons i tend to button one at least or two, while jacket with zip i decide to wear it open more since it has to start from the bottom everytime, most likely i half zip it when start wearing it, but after unzip it when sitting or driving, then I dont bother to zip it again for the rest of the day.It's so much a taste thing. isn't it? To me buttons would seem pretty ostentatious on that pattern but a nice period look. The look I particularly dislike is the cross zip, 1980's rock-n-roller look. The Bootlegger certainly avoids that particular image.
You’re never too old to rock! I plan to be buried in my Vanson Model E, and I second @handymike a mouton collar makes everything look better.